GPS Solutions

, Volume 21, Issue 4, pp 1535–1548 | Cite as

Evaluation of NTCM-BC and a proposed modification for single-frequency positioning

  • Xiaohong Zhang
  • Fujian Ma
  • Xiaodong RenEmail author
  • Weiliang Xie
  • Feng Zhu
  • Xin Li
Original Article


Ionospheric delay is a dominant factor that affects the accuracy of single-frequency positioning. Thus, an empirical ionospheric model with high accuracy is very important for single-frequency users. This study proposes a modified empirical broadcast ionospheric model, called MNTCM-BC, based on the Neustrelitz Total Electron Content (TEC) broadcast model NTCM-BC. Nine daily ionospheric coefficients of these models are estimated using datasets of the previous day from 30 globally distributed Global Navigation Satellite System monitor stations, and the prediction performance of the MNTCM-BC is evaluated with the datasets of the current day from all 300 verification stations. The results show that the complex behavior of the ionosphere is well described by the MNTCM-BC, including the visibility of two ionization crests on both sides of the geomagnetic equator and the TEC variations that depend on the local time and geomagnetic latitude. In terms of the prediction accuracy, compared with the NTCM-BC, the main improvement in the MNTCM-BC is achieved in summer, whereas the accuracy is comparable in other seasons. Hence, the following analyses are focused on summer. In the low-solar activity year of 2009, the prediction accuracy of the MNTCM-BC is improved by 0.11 TECU compared with that of the NTCM-BC. As to the high-solar activity year of 2014, the corresponding improvement is 0.35 TECU. In addition, when the number of monitor stations is increased from 30 to 300, the prediction accuracy of two models can be slightly improved by 0.06 TECU in 2009 and 0.13 TECU in 2014, respectively, while reliability enhances. Furthermore, the average three-dimensional positioning accuracy of 160 globally distributed stations for single-frequency point positioning using the Klobuchar model, the NTCM-BC and the MNTCM-BC is 1.83, 1.21 and 1.20 m during quiet day and 3.15, 2.31 and 2.21 m during perturbed day, respectively. Relative to the Klobuchar model and the NTCM-BC, the average accuracy improvements in the MNTCM-BC are about 30 and 3%, respectively.


Ionospheric delay GNSS Broadcast ionospheric model Ionization crests Single-frequency positioning Modified Neustrelitz TEC broadcast model (MNTCM-BC) 



We would like to express our gratitude to reviewers for their helpful remarks. Additionally, we acknowledge the IGS, SIDC and ISGI for providing access to GNSS data and products, sunspot number and geomagnetic indices, respectively. This study is supported by National Natural Science Foundation of China (Grant No. 41474025), the Surveying and Mapping Foundation Research Fund Program, National Administration of Surveying, Mapping and Geoinformation (Grant No. 14-02-09) and the Open Foundation of Key Laboratory of Precise Engineering and Industry Surveying of the National Administration of Surveying, Mapping and Geoinformation (Grant No. PF2015-5).


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Copyright information

© Springer-Verlag Berlin Heidelberg 2017

Authors and Affiliations

  • Xiaohong Zhang
    • 1
    • 2
  • Fujian Ma
    • 1
  • Xiaodong Ren
    • 1
    Email author
  • Weiliang Xie
    • 1
  • Feng Zhu
    • 1
  • Xin Li
    • 1
  1. 1.School of Geodesy and GeomaticsWuhan UniversityWuhanChina
  2. 2.Collaborative Innovation Center for Geospatial TechnologyWuhanChina

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